When text is longer than the width of a column and text wrapping is turned off?

It depends, if the next cell is blank that the cell will extend normally to allow the text to be displayed.

However, if the cell is occupied it will display something along the lines of # to indicate the column width is not sufficient; the solution to which are as follows:

1. Extend the column width by placing your arrow on the line next to the letter until your cursor changes and click and drag to the desired width.
2. Set the cell to 'wrapped text' by right clicking on the cell and going to format, and extend the row height using the same method as mentioned in 1. but with the row instead of the column.
3. Reduce the length of the text in the cell
4. Reduce the font size of the text in the cell